TAMPA BAY (Reuters) - Vincent Lecavalier scored in the final seconds of overtime to give the Tampa Bay Lightning a dramatic 4-3 victory over the St. Louis Blues on Sunday.

Lecavalier converted a backhand with seven seconds left in the extra session as the Lightning (33-16-5) maintained a three-point lead in the Southeast Division over the Washington Capitals, who earlier blanked Pittsburgh 3-0.

A St. Louis holding penalty set up Lecavalier's power-play that ended a back-and-forth affair and sent the Blues to their fifth loss in the last six games.

"Relentless. That's how we played today," Lecavalier told reporters. "To have a crowd like that (on the day of the Super Bowl) encouraging us was great."

Steven Stamkos scored his NHL-leading 40th goal in the first period to open the scoring, and Patrik Berglund answered for St. Louis 30 seconds into the second period before Dominic Moore restored Tampa Bay's lead about two minutes later.

David Backes and Nikita Nikitin netted back-to-back scores to give the Blues a 3-2 lead at 13:09 in the second but Steve Downie's goal 30 seconds later tied it at 3-3.

Both teams went scoreless in the third.

The Lightning controlled the action in the overtime, outshooting the Blues 9-1.

Ty Conklin made 36 saves for St. Louis in his second start for injured goaltender Jaroslav Halak while Tampa Bay goalie Dan Ellis made 29 stops.

Stamkos had three assists on the day as the Lightning recovered from Friday's 5-2 loss to the Washington Capitals.

"As a line we didn't have a very good game (Friday), so we made sure we came out and did everything to help our team," said Stamkos. "We didn't wait for things to happen, we went out and made things happen."

The Lightning have won seven of eight overall.

(Writing by Jahmal Corner in Los Angeles; Editing by Frank Pingue in Toronto)